The researchers examined data from 51 previously published studies that followed middle-aged and elderly people in North America, Europe and East Asia for at least several years to see if their sleep problems were linked to cognitive health.The study concluded that those who suffer from insomnia increase their risk of developing cognitive problems by 27 percent, while those who suffer from sleep disorders or do not get enough rest, they have a 25 percent increased risk of dementia.
The study team, which was published in the journal Neurology, Neurology and Psychiatry, specialized in Neurology and Mental Health, added that insufficient sleep or spending a long time in bed in insomnia was associated with a 24 percent increase in the risk of cognitive decline.
“These results indicate that sleep regulation may be a promising goal to prevent dementia,” said lead researcher Dr. Wei Shuo from Qingdao University in China.
He explained that the possible explanations for the connection between the two things are that sleep problems cause inflammation in the nerves, which in turn leads to cognitive impairment, and sleep disorders also exacerbate the effect of a lack of oxygen delivery to the brain.
He added that sleep disorders also reduce the effectiveness of the brain in getting rid of toxins and contribute to damage to brain cells or parts of the brain.
The study showed that those who slept about six or seven hours at night had the lowest risk of cognitive disorders, while the odds increased for those sleeping less than four hours or more than 10 hours at night.
“We still need more evidence to see if disturbed sleep leads to dementia and whether improved sleep may reduce such a risk,” said Matthew Pace, a researcher at the University of Melbourne in Australia, who was not involved in the study.
But he added by email, “Sleep is very important to public health and should be a priority.”